TECHNICAL FIELD

The present invention relates to a compact machine tool with a spindle unit comprising a vertically movable spindle, and with a drive assembly which moves the spindle unit in the vertical direction.

BACKGROUND OF THE INVENTION

It is well known that the machine tools (within the scope of the invention, the term “machine tool” should be understood as “metal cutting machine” or “machining center” or “metal working center”, preferably numerically controlled (NC) or computerized numerically controlled (CNC) machines) have a variety of structural forms and functions. The machine tool of the present invention has a spindle unit comprising a spindle movable in the vertical direction, and this spindle unit can be moved separately from the spindle by a drive assembly in the vertical direction.

The machine tool according to the invention typically comprises a main body, to which the workpiece to be machined is coupled and which is positioned on the base. The main body comprises a longitudinal form which typically has a transverse dimension. The machine tool according to the invention further comprises a crossbeam extending along the width of the main body and above the main body. The crossbeam is supported to the main body by two opposite ends. Thus, the workpiece can be positioned in the space in the vertical direction between the crossbeam and the main body.

A spindle unit which is arranged to move along the axis commonly referred to as Y-axis in the field of the machine tools and representing the axis direction of the crossbeam is supported to the crossbeam. The spindle unit comprises a spindle which can be moved along the axis commonly referred to as Z-axis.

As mentioned above, the spindle unit can also be moved separately from the spindle by a drive assembly in the vertical direction. The machine tools known in the art drive the crossbeam (and hence the spindle unit supported thereto) for moving the spindle unit in the vertical direction (usually referred to as W-axis). Thus, the W-axis is parallel to the Z-axis.

The known machine tools comprise columns extending oppositely in the vertical direction, and such machine tools are commonly referred to as “double-column” machine tools. The columns extending oppositely support the crossbeam (and hence the spindle unit supported thereto) in the vertical direction. The movement in the W- axis takes place by the collective actuation of the crossbeam (and hence the spindle unit supported thereto). Such an embodiment has several disadvantages. First of all, the movement of the crossbeam in the vertical direction (in the W-axis) causes the unnecessary load bearing and therefore power consumption. On the other hand, due to the large mass of the crossbeam, the vertical movement of the spindle unit is quite slow, thus reducing the manufacturing efficiency. Another disadvantage results in that the volume occupied by the machine tool increases unnecessarily.

Another disadvantage of the known machine tools is the large distance between the opposing columns and the spindle in the longitudinal direction of the main body (usually referred to as X-axis). The measure of this distance in the X-axis direction is related to the machining precision of the machine tool. Yet, it will cause the elastic displacement of the columns and, as a result, the target position precision of the spindle will deteriorate since the forces acting on the spindle from the workpiece during machining will increase the bending moments on the column bearings as this distance increases.

The representative views of the configuration in the state of the art are given in Fig. 1 and Fig. 2 in the appendix. Figure 1 shows, in a perspective view, the spindle (P1) of a machine tool, the crossbeam (P2) to which this spindle is coupled, and the opposing vertical columns (P3) to which this crossbeam is coupled. The crossbeam is also moved for the vertical (in the W-axis) movement of the spindle unit. Fig. 2 is a representative side view of Fig. 1. The distance (P4) on the X-axis between the vertical axis of the spindle and the columns is clearly visible.

BRIEF DESCRIPTION OF THE INVENTION

The object of the invention is to provide a machine tool which is efficient in terms of compactness. Another object of the invention is to provide a machine tool which is efficient in terms of power consumption.

Another object of the invention is to provide a machine tool which has an improved machining precision.

To achieve this objects, the present invention relates to a machine tool comprising a main body placed on a base, a crossbeam spaced apart over the main body and transversally extending to the main body, two crossbeam supports extending vertically and oppositely one another for supporting the crossbeam to the main body, a spindle unit support coupled to the crossbeam in a way to be movable along the axis of the crossbeam, a spindle unit having a spindle, the spindle unit being coupled to the spindle unit support, a spindle drive means for moving the spindle along the vertical axis (Z-axis), characterized in that a spindle unit drive means is provided for moving the spindle unit along the vertical axis (W-axis).

According to an embodiment of the invention, the crossbeam is arranged to only move along the direction of the main body rail (X axis).

According to an embodiment of the invention, the spindle unit is coupled to the spindle unit support in such a way that when the spindle unit is moved the crossbeam is not moved in the vertical direction.

According to an embodiment, the invention comprises a carrier coupled to the spindle unit support in a way to be movable along the vertical axis (W-axis). The carrier is coupled to the spindle unit in such a way that it can move the spindle unit in the vertical direction.

According to an embodiment of the invention, the spindle unit is configured in such a way that it is located between the spindle unit support and carrier based on X-axis. The side of the spindle unit support facing the spindle unit has the form of a cylindrical sector. Similarly, the side of the carrier facing the spindle unit has the form of a cylindrical sector. In this case, the spindle unit is cylindrically surrounded partly by the spindle unit support and partly by the carrier in the vertical direction. According to an embodiment of the invention, the axis of the resultant center of gravity of this components (spindle unit, carrier, and spindle unit support) is, based on X-axis, essentially in the same position as the vertical axis connecting the spindle unit support to the carrier. On the other hand, the vertical axis connecting the spindle unit support to the carrier is, based on X-axis, essentially in the same position as the vertical axis connecting the spindle unit to the carrier. With this configuration, the machining precision is improved by minimizing the vibration that may be created by these components (spindle unit, carrier, and spindle unit support) on the spindle.

BRIEF DESCRIPTION OF THE FIGURES

Fig. 1 shows a representative perspective view of a prior art machine tool.

Fig. 2 shows a side view of Fig. 1 of the prior art.

Fig. 3 shows a representative perspective view of a machine tool according to the invention.

Fig. 4 shows a representative front view of the carrier and spindle unit on a machine tool in an upper position, according to a first embodiment of the invention.

Fig. 5 shows a representative front view of the carrier and spindle unit on a machine tool in a lower position, according to a first embodiment of the invention.

Fig. 6 shows a representative side view of the machine tool, according to a first embodiment of the invention.

Fig. 7 shows a representative plan view of the machine tool, according to a first embodiment of the invention.

Fig. 8 shows a representative perspective view of the machine tool, according to a second embodiment of the invention.

Fig. 9 shows a simplified perspective view of Fig. 8. Fig. 10 shows a representative plan view of the machine tool, according to a second embodiment of the invention.

Fig. 11 shows a representative perspective view of the spindle unit, according to the invention.

Fig. 12 shows a representative perspective view of the spindle unit and carrier, according to the invention.

Fig. 13 shows a representative perspective view of the spindle unit, carrier, and spindle unit support, according to a second embodiment of the invention.

Fig. 14 shows a representative side view of the machine tool, according to a second embodiment of the invention.

Fig. 15 shows a representative plan view of the sub-parts of the machine tool, according to a second embodiment of the invention.

DESCRIPTION OF THE PARTS IN THE FIGURES

1 Main body

2 Main body rail

2.1 Rail support

3 Main body base

3.1 Space

4 Workpiece table

5 Crossbeam

5.1 Crossbeam guide

5.2 Front side

5.3 Rear side

5.4 Lateral side

6 Crossbeam support

7 Crossbeam motor

8 Crossbeam rail

9 Spindle unit support 9.1 Rear side of the support collar

9.2 Front side of the support collar

9.3 Support guide

9.4 Support collar

9.5 Upper support part

10 Carrier

11 Carrier motor

12 Carrier motor shaft

13 Carrier guide

14 Carrier rail

15 Carrier blade

16 Spindle unit

17 Spindle

18 Spindle motor

18.1 Spindle motor shaft

19 Spindle blade

20 Spindle guide

21 Spindle rail

22 Support motor

A Axis

P1 Spindle in the drawing of the prior art

P2 Crossbeam in the drawing of the prior art

P3 Vertical column in the drawing of the prior art

P4 Distance in the drawing of the prior art

DETAILED DESCRIPTION OF THE INVENTION

Fig. 3 shows a representative perspective view of the machine tool according to the invention. The machine tool comprises a main body (1) extending along the X-axis.

Two main body rails (2) are arranged, which extend oppositely at a distance from one another along the main body (1). The main body (1) comprises a main body base (3) arranged in the Y-axis direction between the main body rails (2). A workpiece table (4), on which the workpiece is placed, is provided on the main body base (3). The position of the workpiece table (4) in the X-axis direction can be fixed; on the other hand, as is known from the art, this table (4) can be moved linearly along the X-axis. The main body rails (2) can be provided at the top of each of the rail supports (2.1) extending oppositely and vertically upwards from the main body base (3).

The machine tool comprises a crossbeam (5) extending transversally. A crossbeam support (6) is provided at each of two opposite ends of the crossbeam (5). Each crossbeam support (6) comprises a crossbeam guide (5.1) provided at its lower sides and supported to the main body rails (2). At least one crossbeam motor (7) is provided in such a way that each crossbeam support (6) is preferably in close proximity to the respective crossbeam guide (5.1). The motors referred to in this description may be the electronically controlled motors such as servo motors. As is known in the art, the crossbeam (5) is moved in the X-axis direction by sliding the crossbeam guide (5.1) over the main body rail (2) with the drive of the crossbeam motor (7). As mentioned above, it is also possible to move the workpiece table in the X-axis direction; in this case, it should be appreciated that the position of the crossbeam (5) can be fixed.

As shown in Fig. 5, there is a space (3.1) between the lower end of the crossbeam (5) and the main body base (3) so that the workpiece can be positioned.

The crossbeam (5) and the crossbeam supports (6) may be the discrete components that can be mounted together, or these components may be integral. The crossbeam (5) comprises a crossbeam rail (8) extending along the Y-axis. The number of these rails (8) can be selected in accordance with the purpose, two crossbeam rails (8) are shown in the accompanying figures. According to one embodiment of the invention, one of the crossbeam rails is provided at the top of the crossbeam (5) and the other rail is provided at the bottom of the crossbeam (5) at a distance from the upper rail.

A spindle unit support (9) movable in the Y-axis direction is slidingly coupled to the crossbeam (5). This form of supporting can be provided by means of the guide pieces known from the art or provided for the spindle unit support (9) and the crossbeam rails (8) as described above. The spindle unit support (9) can be moved by the support motors (22) shown in Fig. 7. As can be seen in Fig. 3 and Fig. 6, the side profile of the crossbeam (5) has a relatively large width in the X-axis direction on its lower side (on the side close to the base) and has an upwardly decreasing width (in the Z-axis direction). The side profile of the spindle unit support (9) has a relatively small width in the X-axis direction on its lower side (on the side close to the base) and has an upwardly increasing width (in the Z-axis direction).

As can be seen in Fig. 4 or Fig. 5, a spindle unit (16) comprising a spindle (17) with a preferably longitudinal form is supported to a carrier (10) so that it can move in the Z- axis direction and the carrier (10) is supported to the spindle unit support (9) so that it can move in the W-axis direction. Thus, the carrier (10) can move the spindle unit (16) as a whole in the vertical direction and the spindle (17) can also be moved in the vertical direction. The spindle unit support (9) comprises two carrier rails (14) extending vertically and oppositely, and the carrier (10) comprises carrier guides (13) corresponding to each of these carrier rails. Similarly, the spindle unit (16) comprises two spindle rails (21) extending vertically and oppositely, and the carrier (10) comprises spindle guides (20) corresponding to each of these spindle rails.

A carrier blade (15) is provided on the upper side of the carrier (10). At least one, preferably two, drive means, extending along the carrier blade (15), preferably a carrier motor (11), are arranged. The carrier motors (11) are coupled to a carrier motor shaft (12) extending downwards from them. These carrier motor shafts (12) can be threaded shafts. A spindle blade (19) is provided on the upper side of the spindle unit (16). At least one, preferably two, drive means, extending along the spindle blade (19), preferably a spindle motor (18), are arranged. The spindle motors (18) are coupled to a spindle motor shaft (18.1) extending downwards from them. These spindle motor shafts (18.1) can be threaded shafts. Since the carrier motor shafts (12) are coupled to the carrier guides (13), the spindle unit (16) shown in Fig. 11 is moved by the carrier (10) in the vertical direction (W-axis) by driving these carrier motor shafts (12). Since the spindle motor shafts (18.1) are coupled to the spindle guides (20), the spindle (17) is moved in the vertical direction (Z-axis) by driving these spindle motor shafts (18.1).

It should be appreciated that instead of the above-mentioned carrier motor (11) and spindle motor (18), other drive means, for example hydraulic motors, can be used.

As seen in Fig. 7, according to an embodiment of the invention, the side of the spindle unit support (9) facing the spindle unit (16) comprises a cylindrical sector form. Similarly, the side of the carrier (10) facing the spindle (16) unit comprises the form of a cylindrical sector. Thus, the spindle unit (16) is cylindrically surrounded by the spindle unit support (9) and the carrier (10).

According to an embodiment of the invention, the axis A of the resultant center of gravity of the spindle unit (16), the carrier (10), and the spindle unit support (9) is, based on X-axis, essentially in the same position as the vertical axis in which the spindle unit support (9) is supported by the carrier (10), as seen in Fig. 7. On the other hand, the vertical axis in which the spindle unit support (9) is supported by the carrier (10) is, based on X-axis, essentially in the same position as the vertical axis in which the spindle unit (9) is supported by the carrier (10). Thus, the vibration that may be created by said components (the spindle unit (16), the carrier (10), and the spindle unit support (9)) on the spindle (17) is minimized.

According to an embodiment of the invention as shown in Fig. 3 to Fig. 7, the spindle unit support (9) is slidingly supported to the crossbeam (5) from one side (from the rear side 9.1) in the Y-axis. According to a second embodiment of the invention, the spindle unit support (9) can be supported to the crossbeam (5) from two sides, that is, from both the support rear side (9.1) and the support front side (9.2). In such an embodiment, as seen in Fig. 14, the spindle unit support (9) may consist of a vertically extending upper support part and an associated horizontally extending support collar (9.4).

As seen in Fig. 9, the crossbeam (5) may have a hollow, frame-like, or block-like form comprising a front side (5.2), a rear side (5.3) and the opposite lateral sides (5.4) joining the front side and rear side. Two crossbeam rails (8) which preferably extend oppositely and parallel to one another are arranged so that one is on the front side (5.2) and the other one is on the rear side (5.3) of the crossbeam. The lower portions of the front side of the support collar (9.2) and the rear side of the support collar (9.1) are each provided with a support guide (9.3) as described above in the first embodiment. When the support guides (9.3) are fitted on the respective crossbeam rails (8), the spindle unit support (9) is moved by the motor drive means in the Y-axis. The moving assemblies of the spindle unit (16) and the carrier (10) in the vertical direction (Z-axis and W-axis) are as in the first embodiment of the invention above. According to the second embodiment of the invention, the length of the spindle unit support (9) in the X-axis direction is preferably greater than the length of the carrier (10) and the spindle unit (16) in the X-axis direction; at least these lengths may be equal to each other, for instance.

According to the second embodiment of the invention, the spindle unit support is supported to the crossbeam (5) from both the rear side (9.1) and the front side (9.2), thus increasing advantageously the machining precision by benefiting from the reduction of the vibration against the forces acting on the spindle (17) from the workpiece.

As mentioned above in the first embodiment of the invention, the axis A of the resultant center of gravity of the spindle unit (16), the carrier (10), and the spindle unit support

(9) is, based on X-axis, essentially in the same position as the vertical axis in which the spindle unit support (9) is supported by the carrier (10), as seen in Fig. 15. On the other hand, the vertical axis in which the spindle unit support (9) is supported by the carrier

(10) is, based on X-axis, essentially in the same position as the vertical axis in which the spindle unit (9) is supported by the carrier (10). The distance of the axis A of the resultant center of gravity from each crossbeam rail (8) is essentially equal.